In recent years, advances in technology, as well as evolving tastes in style, have led to substantial changes in the design of automobiles. One of the changes involves the power usage and complexity of the various electrical systems within automobiles, particularly alternative fuel vehicles, such as hybrid, electric, and fuel cell vehicles. Many of these vehicles use electric motors, such as induction motors, to convert electrical power to mechanical power to provide traction power to the vehicle.
Motor vehicle applications typically employ a three-phase AC induction motor. In an induction motor, a stator includes a number of wound poles carrying supply current to induce a magnetic field that penetrates the rotor. Typically, an electronic control system generates duty cycle commands based on the torque commanded by the driver and measured system quantities. Based on the duty cycle commands, an inverter assembly then applies an appropriate voltage to produce current commands for the induction motor.
The electronic control system typically commands both d- and q-axis currents. In particular, the d-axis current command is generated based on a d-axis flux linkage command derived from the torque command and current operating conditions. Some conventional systems may have a delay between the torque command and the actual torque response. Particularly, during transient time periods, the true d-axis flux linkage changes slower than the d-axis current on which it is built as a result of the inherent rotor time constant of the motor, which may cause the torque delays.
Accordingly, it is desirable to have improved control systems and methods that reduce torque delay in induction motors. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.